Field of the Invention
The present invention relates to a developing apparatus, a developing cartridge, a process cartridge, and a method of manufacturing molded articles.
The developing apparatus is apparatus including a developing roller, and configured to visualize an electrostatic latent image formed on an electrophotographic photosensitive drum by using developer (hereinafter, referred to as toner) with the developing roller.
The developing cartridge is formed by integrating the developing apparatus into a cartridge, and is demountably mounted on a main body of an electrophotographic image forming apparatus. The process cartridge includes the electrophotographic photosensitive drum and the developing apparatus configured to act on the electrophotographic photosensitive drum integrated into the cartridge and is configured to be demountably mounted on the main body of the electrophotographic image forming apparatus.
Description of the Related Art
An electrophotographic image forming apparatus using an electrophotography forming process of the related art employs a process cartridge system including an electrophotographic photoreceptor and a process device acting thereon integrated into a cartridge so as to allow the cartridge to be demountably mountable on a main body of the electrophotographic image forming apparatus.
According to the process cartridge system, maintenance of the apparatus can be performed by users themselves without resort to a serviceman, and hence operability is significantly improved. Therefore, the process cartridge system is widely used in the electrophotographic image forming apparatus.
In the case of the electrophotographic image forming apparatus employing the process cartridge system, the process cartridge is replaced by the users as described above. Therefore, an amount-of-remaining-toner sensing device configured to sense consumption of toner, and notify time for replacement to the users is often provided.
Examples of the amount-of-remaining-toner sensing device include a system that senses a change in electrostatic capacitance between a plurality of electrodes arranged in the process cartridge and senses an amount of remaining toner. As an example of the system as described above, Japanese Patent Laid-Open No. 2003-248371 proposes a configuration in which a developer bearing member is used as an input-side electrode by applying an AC bias thereto, and an electrostatic capacitance sensing member serving as an output-side electrode is provided at a position opposing the developer bearing member in the developing apparatus. In this configuration, a contact member configured to electrically connect the electrostatic capacitance sensing member and a conductive member having a spring property provided in the main body of the image forming apparatus (hereinafter, referred to as a main body-side amount-of-remaining-toner contact) is provided on the process cartridge. When the AC bias is applied to the developer bearing member, an electric current depending on the electrostatic capacitance (the amount of remaining toner) is induced between the developer bearing member and the electrostatic capacitance sensing member. The amount of remaining toner can be sensed successively by measuring a current value of an induced current with an amount-of-remaining-toner sensing unit in the main body of the image forming apparatus via the contact member provided on the process cartridge side and the main body-side amount-of-remaining-toner contact.
In the method of the related art, highly precise arrangement of many components such as keeping a distance between a member for sensing the electrostatic capacitance and the developer bearing member constant is required for sensing the amount of developer accurately in high degree of precision.